Increase of glycol removal efficiency in the receiving facilities of a gas plant

Abstract

When gas is dried at the platforms connected to the Åsgard transport pipe, it is used TEG. Because of the high pressures from the fields, some of the TEG will enter a gas phase and become carried over with the gas. At the Åsgard inlet facilities at Kårstø the TEG is recovered by separators. The separation efficiency of the current separators is not sufficient, and in this assignment there will be investigation on how the glycol separation can get better. There is a focus on the letdown station and the two filter separators in the KUP train. The methodology used in this study includes literature study, contact with vendors of new separation technology and valves. This study is based on a report from Statoil’s R&D center in Trondheim. The valves at the letdown station have been consider replaced with the Twister SwirlValve™ to minimize turbulence created in the flow upstream the separators. This could help the separation because the size range distribution of droplets would probably decrease, and therefore get easier to separate. The effect this change would have on the glycol recovery efficiency is impossible to determine, and Statoil have to decide rather or not they want to do a test on the Twister SwirlValve™ in this application. The current separators have been evaluated for further use with new internals, but calculations show that they are undersized. Further on there is evaluations of new separators and internals, both vertical and horizontal. The conclusion is that a new separator should be horizontal to prevent a large intervention at the plant. The new horizontal separator should contain a vane type inlet device as a primary separation and HiPer cyclones or a combination of mesh and vane as demister.